Posted by Damir [ 213.202.84.152 ] on May 20, 2005 at 08:13:05:

In Reply to: one is on my list... posted by Tnuctipun on May 20, 2005 at 06:44:59:

I have two pairs, bought as "matched", but for the differential "work" they probably need some "trimming" (high gm = small change in Ugk=large change in Ia). Fantastic tube, high µ and gm, 1mm thick Ti-anode, Pt- grid wire, very linear, but needs some attention to avoid "transistor sound" (k5) - better run on lower current (by Pete Millett measurements). Then oscillations are higly possible, maybe best to use "stoppers" on both grid connections, and all four cathode connections.
It`s high on my list too (300B driver), but too many other options to try, and I`m too lazy...
Another not so good feature is that it needs bias in the -2...2,5V area, broadly speaking, and cannot "accept" full 2Vrms signal from CD source... And we need about 2*55Vrms input (min.) in 300B pair...not so easy even for 6S45Pi in diff. driver. But, one stage driver sounds good:-).
At least, if nothing concretly, I posted the picture:-)

Replies:

• 6S45Pi diff pair input signal headroom - Tnuctipun 08:55:29 05/20/05 (7)
  • Re: 6S45Pi diff pair input signal headroom - Damir 15:05:07 05/20/05 (6)
    • but, but, but... - Tnuctipun 19:10:03 05/21/05 (5)
      • Re: but, but, but... - Damir 03:00:29 05/22/05 (4)
        • so then.... - Tnuctipun 08:27:12 05/22/05 (3)
          • Re: so then.... - manualblock 19:01:52 05/23/05 (2)
            • Re: so then.... - Tnuctipun 20:08:29 05/23/05 (1)
              • Re: so then.... - manualblock 06:37:01 05/24/05 (0)